Breaking News! Scientists just figured out why skunkweed smells like a skunk’s ass!!!!
For a very long time, scientists had no idea precisely which molecule gave ween that signature nauseating scent. Most research on the malodorous smell had focused on terpenes and terpenoids. These were the primary suspects because they are hydrocarbons that give most plants their smell.
Cannabis sativa L. produces more than 200 known aroma compounds. Prior studies have focused mainly on terpenoids — molecules that range in odor from fuel-like to woody, citrusy or floral. Different cannabis cultivars have diverse mixtures of these compounds that contribute to their unique aromas.
However, although terpenoids are the most abundant aroma compounds in cannabis, there is little evidence that they provide the underlying skunk-like smell of many cultivars. Skunks use several VSCs in their smelly defense sprays, so Iain Oswald and colleagues suspected that there could be similar molecules in cannabis. The team decided to use sensitive analytical techniques to find out.
Now, researchers reporting in ACS Omega have discovered a new family of prenylated volatile sulfur compounds (VSCs) that give cannabis its characteristic skunky aroma. The findings open up opportunities to investigate the molecules for medicinal benefits, the researchers say. We can find other families of VSCs in more pleasantly aromatic like garlic and hops. But we also find VSCs in less delicious places like the defensive spray used by skunks.
The researchers analyzed flowers from 13 cannabis cultivars using a custom-built 2D gas chromatography system with three different types of detectors. Then, a four-person panel ranked the pungency of the cultivars on a scale from 0 to 10. The most pungent one, called Bacio Gelato, had the highest concentration of VSCs. The team identified seven VSCs in this cultivar, some of which were also present in other cultivars. Five of the VSCs contained the prenyl functional group and had skunk-like or sulfuric aromas. One compound in particular, 3-methyl-2-butene-1-thiol, referred to as VSC3, was the most abundant VSC in the cultivars that the panel reported to be most pungent.
To confirm that VSC3 was the main source of the skunk-like aroma, the team added it to a mixture of 10 other major aroma compounds from cannabis, producing a combined odor very similar to the characteristic scent of cannabis. They also detected VSC3 in cannabis concentrates, such as those used for vaping. Finally, in greenhouse experiments, the researchers determined that the prenylated VSCs increased significantly toward the end of the flowering stage of cannabis growth, reached a maximum during curing and then dropped substantially after 10 days of storage.
So it turns out common intuition was correct in describing the weed scent as skunky or calling it skunkweed. Now that the skunk molecule has been identified will new research be done to weed it out of the weed if you’ll pardon the pun.
- Iain W. H. Oswald, Marcos A. Ojeda, Ryan J. Pobanz, Kevin A. Koby, Anthony J. Buchanan, Josh Del Rosso, Mario A. Guzman, Thomas J. Martin. Identification of a New Family of Prenylated Volatile Sulfur Compounds in Cannabis Revealed by Comprehensive Two-Dimensional Gas Chromatography. ACS Omega, 2021; 6 (47): 31667 DOI: 10.1021/acsomega.1c04196